Additive manufacturing of architectured materials

ABSTRACT

This disclosure provides a scalable and reproducible process to create complex 3D metal materials with sub-micron features by applying lithographic methods to transparent metal- or inorganic-rich polymer resins.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional application and claims priority to U.S.application Ser. No. 15/719,338, filed Sep. 28, 2017, which applicationclaims the benefit of U.S. Provisional Patent Application No.62/401,039, filed Sep. 28, 2016, all of which are incorporated herein inby reference in their entirety for any and all purposes.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

This invention was made with government support under Grant No.N00014-16-1-2827 awarded by the Office of Naval Research. The governmenthas certain rights in the invention.

FIELD

The invention relates to methods of manufacturing micro- and nano-scaledmaterials.

BACKGROUND

Methods for additive manufacturing (AM) of metals are limited to 20-50μm resolution, which renders them inapplicable for generating complex3D-printed metals with smaller features. Efforts have been devoted tofabricating metal structures with smaller dimensions; today noestablished 3D-printing of metals exists at the micron scale.

SUMMARY

The disclosure provides a lithography-based process to create complex 3Dnano- and/or micro-architected materials comprising metals, metal ions,metalloids, inorganic, and inorganic-organic hybrid materials(“framework materials”) with about 5 to 100 nm resolution. The processuses a photopolymerizable resist containing the framework material. Theprocess uses, for example, a two-photon lithography technique to sculpt3D polymer scaffolds. These scaffolds can then be heat treated (e.g.,pyrolyzed) to volatilize any organics, thereby leaving the frameworkmaterial in a desired architectural format. Using the method, thedisclosure provides the ability to produce 3D-printed micro- andnano-architected material including, for example, metal frameworks andstructures.

The disclosure provides a composition comprising a hybridorganic-inorganic polymer resin comprising photopolymerizable functionalgroups having the general structure:

M^(n+)(—R′OC—R)_(n)

where M is a metal, a metal ion, a metalloid, a metal alloy, a metaloxide, a metal nitride, an inorganic, a metal-inorganic composite, acarbon-based material and/or an inorganic-organic hybrid material,wherein R is an alkene or a C₂₋₁₀ terminal alkene and R′ is N, O, F, Sor Cl and wherein n is 1, 2, 3, 4, 5 or 6. In one embodiment, the hybridorganic-inorganic polymer resin has the formula R—COR′-M²⁺—R′OC—R,wherein M is a divalent metal ion, alloy, or inorganic material, R is analkene or C₂₋₁₀ terminal alkene and R′ is N, O, F, S or Cl. In anotherembodiment, the metal ion is selected from the group consisting of Li⁺,Na⁺, K⁺, Rb⁺, Cs⁺, Be²⁺, Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺, Sc³⁺, Sc²⁺, Sc⁺, Y³⁺,Y²⁺, Y⁺, Ti⁴⁺, Ti³⁺, Ti²⁺, Zr⁴⁺, Zr³⁺, Zr²⁺, Hf⁴⁺, Hf³⁺, V⁵⁺, V⁴⁺, V³⁺,V²⁺, Nb⁵⁺, Nb⁴⁺, Nb³⁺, Nb²⁺, Ta⁵⁺, Ta⁴⁺, Ta³⁺, Ta²⁺, Cr⁶⁺, Cr⁵⁺, Cr⁴⁺,Cr³⁺, Cr²⁺, Cr⁺, Cr, Mo⁶⁺, Mo⁵⁺, Mo⁴⁺, Mo³⁺, Mo²⁺, Mo⁺, Mo, W⁶⁺, W⁵⁺,W⁴⁺, W³⁺, W²⁺, W⁺, W, Mn⁷⁺, Mn⁶⁺, Mn⁵⁺, Mn⁴⁺, Mn³⁺, Mn²⁺, Mn⁺, Re⁷⁺,Re⁶⁺, Re⁵⁺, Re⁴⁺, Re³⁺, Re²⁺, Re⁺, Re, Fe⁶⁺, Fe⁴⁺, Fe³⁺, Fe²⁺, Fe⁺, Fe,Ru⁸⁺, Ru⁷⁺, Ru⁶⁺, Ru⁴⁺, Ru³⁺, Ru²⁺, Os⁸⁺, Os⁷⁺, Os⁶⁺, Os⁵⁺, Os⁴⁺, Os³⁺,Os²⁺, Os⁺, Os, Co⁵⁺, Co⁴⁺, Co³⁺, Co²⁺, Co⁺, Rh⁶⁺, Rh⁵⁺, Rh⁴⁺, Rh³⁺,Rh²⁺, Rh⁺, Ir⁶⁺, Ir⁵⁺, Ir⁴⁺, Ir³⁺, Ir²⁺, Ir⁺, Ir, Ni³⁺, Ni²⁺, Ni⁺, Ni,Pd⁶⁺, Pd⁴⁺, Pd²⁺, Pd⁺, Pd, Pt⁶⁺, Pt⁵⁺, Pt⁴⁺, Pt³⁺, Pt²⁺, Pt⁺, Cu⁴⁺,Cu³⁺, Cu²⁺, Cu⁺, Ag³⁺, Ag²⁺, Ag⁺, Au⁵⁺, Au⁴⁺, Au³⁺, Au²⁺, Au⁺, Zn²⁺,Zn⁺, Zn, Cd²⁺, Cd⁺, Hg⁴⁺, Hg²⁺, Hg⁺, B³⁺, B²⁺, B⁺, Al³⁺, Al²⁺, Al⁺,Ga³⁺, Ga²⁺, Ga⁺, In³⁺, In²⁺, In¹⁺, Tl³⁺, Tl⁺, Si⁴⁺, Si³⁺, Si²⁺, Si⁺,Ge⁴⁺, Ge³⁺, Ge²⁺, Ge⁺, Ge, Sn⁴⁺, Sn²⁺, Pb⁴⁺, Pb²⁺, As⁵⁺, As³⁺, As²⁺,As⁺, Sb⁵⁺, Sb³⁺, Bi⁵⁺, Bi³⁺, Te⁶⁺, Te⁵⁺, Te⁴⁺, Te²⁺, La³⁺, La²⁺, Ce⁴⁺,Ce³⁺, Ce²⁺, Pr⁴⁺, Pr³⁺, Pr²⁺, Nd³⁺, Nd²⁺, Sm³⁺, Sm²⁺, Eu³⁺, Eu²⁺, Gd³⁺,Gd²⁺, Gd⁺, Tb⁴⁺, Tb³⁺, Tb²⁺, Tb⁺, Db³⁺, Db²⁺, Ho³⁺, Er³⁺, Tm⁴⁺, Tm³⁺,Tm²⁺, Yb³⁺, Yb²⁺, Lu³⁺ and alloys of any of the foregoing. In anotherembodiment, the inorganic is a single or mixed oxide, carbide, nitride,silicate, boride of Ti, W, Si, Zr, Al, Y, Cr, Fe, Pb, Co, Ce, Zn, or arare earth element. In another embodiment, the inorganic material isselected from the group consisting of TiO₂, AlO₂, Al₂O₃, ZrO₂, SiC,SiO₂, SiC, CeO₂, and ZnO. In another embodiment, the metal-inorganiccomposite material comprises Au—Ni—TiO₂, Ni—Co—TiO₂, Ni—Zn—Al₂O₃, orNi—B—TiO₂. In another embodiment, of any of the foregoing, thecomposition further comprises a photoinitiator or a photoinitiator and amonomer capable of forming a polymer with the hybrid organic-inorganicpolymer.

The disclosure also provides a method for manufacturing a sub-micronarchitectural material, comprising patterning a hybrid organic-inorganicpolymer resin comprising photopolymerizable functional groups having thegeneral structure:

M^(n+)(—R′OC—R)_(n)

where M is a metal, a metal ion, a metalloid, a metal alloy, a metaloxide, a metal nitride, an inorganic, an inorganic-organic hybrid acarbon-based material and/or a metal-inorganic composite material,wherein R is an alkene or C₂₋₁₀ terminal alkene and R′ is N, O, F, S orCl and wherein n is 1, 2, 3, 4, 5 or 6, wherein the patterning occurs inthe presence of a photoinitiator using a single or two photonlithography technique to polymerize the polymer resin and generate thesub-micron architectural material having desired characteristicdimension of about 5 nm to 5 microns across. In one embodiment, thehybrid organic-inorganic polymer resin has the formulaR—COR′—M²⁺—R′OC—R, wherein M is a divalent metal ion, alloy, orinorganic material, R is an alkene or a C₂₋₁₀ terminal alkene and R′ isN, O, F, S or Cl. In another embodiment, the metal ion is selected fromthe group consisting of Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺, Be²⁺, Mg²⁺, Ca²⁺, Sr²⁺,Ba²⁺, Sc³⁺, Sc²⁺, Sc⁺, Y³⁺, Y²⁺, Y⁺, Ti⁴⁺, Ti³⁺, Ti²⁺, Zr⁴⁺, Zr³⁺, Zr²⁺,Hf⁴⁺, Hf³⁺, V⁵⁺, V⁴⁺, V³⁺, V²⁺, Nb⁵⁺, Nb⁴⁺, Nb³⁺, Nb²⁺, Ta⁵⁺, Ta⁴⁺,Ta³⁺, Ta²⁺, Cr⁶⁺, Cr⁵⁺, Cr⁴⁺, Cr³⁺, Cr²⁺, Cr⁺, Cr, Mo⁶⁺, Mo⁵⁺, Mo⁴⁺,Mo³⁺, Mo²⁺, Mo⁺, Mo, W⁶⁺, W⁵⁺, W⁴⁺, W³⁺, W²⁺, W⁺, W, Mn⁷⁺, Mn⁶⁺, Mn⁵⁺,Mn⁴⁺, Mn³⁺, Mn²⁺, Mn⁺, Re⁷⁺, Re⁶⁺, Re⁵⁺, Re⁴⁺, Re³⁺, Re²⁺, Re⁺, Re,Fe⁶⁺, Fe⁴⁺, Fe³⁺, Fe²⁺, Fe⁺, Fe, Ru⁸⁺, Ru⁷⁺, Ru⁶⁺, Ru⁴⁺, Ru³⁺, Ru²⁺,Os⁸⁺, Os⁷⁺, Os⁶⁺, Os⁵⁺, Os⁴⁺, Os³⁺, Os²⁺, Os⁺, Os, Co⁵⁺, Co⁴⁺, Co³⁺,Co²⁺, Co⁺, Rh⁶⁺, Rh⁵⁺, Rh⁴⁺, Rh³⁺, Rh²⁺, Rh⁺, Ir⁶⁺, Ir⁵⁺, Ir⁴⁺, Ir³⁺,Ir²⁺, Ir⁺, Ir, Ni³⁺, Ni²⁺, Ni⁺, Ni, Pd⁶⁺, Pd⁴⁺, Pd²⁺, Pd⁺, Pd, Pt⁶⁺,Pt⁵⁺, Pt⁴⁺, Pt³⁺, Pt²⁺, Pt⁺, Cu⁴⁺, Cu³⁺, Cu²⁺, Cu⁺, Ag³⁺, Ag²⁺, Ag⁺,Au⁵⁺, Au⁴⁺, Au³⁺, Au²⁺, Au⁺, Zn²⁺, Zn⁺, Zn, Cd²⁺, Cd⁺, Hg⁴⁺, Hg²⁺, Hg⁺,B³⁺, B²⁺, B⁺, Al³⁺, Al²⁺, Al⁺, Ga³⁺, Ga²⁺, Ga⁺, In³⁺, In²⁺, In¹⁺, Tl³⁺,Tl⁺, Si⁴⁺, Si³⁺, Si²⁺, Si⁺, Ge⁴⁺, Ge³⁺, Ge²⁺, Ge⁺, Ge, Sn⁴⁺, Sn²⁺, Pb⁴⁺,Pb²⁺, As⁵⁺, As³⁺, As²⁺, As⁺, Sb⁵⁺, Sb³⁺, Bi⁵⁺, Bi³⁺, Te⁶⁺, Te⁵⁺, Te⁴⁺,Te²⁺, La³⁺, La²⁺, Ce⁴⁺, Ce³⁺, Ce²⁺, Pr⁴⁺, Pr³⁺, Pr²⁺, Nd³⁺, Nd²⁺, Sm³⁺,Sm²⁺, Eu³⁺, Eu²⁺, Gd³⁺, Gd²⁺, Gd⁺, Tb⁴⁺, Tb³⁺, Tb²⁺, Tb⁺, Db³⁺, Db²⁺,Ho³⁺, Er³⁺, Tm⁴⁺, Tm³⁺, Tm²⁺, Yb³⁺, Yb²⁺, Lu³⁺ and alloys of any of theforegoing. In another embodiment, the inorganic is a single or mixedoxide, carbide, nitride, silicate, boride of Ti, W, Si, Zr, Al, Y, Cr,Fe, Pb, Co, or a rare earth element. In another embodiment, theinorganic is selected from the group consisting of TiO₂, AlO₂, Al₂O₃,ZrO₂, SiC, SiO₂, SiC, CeO₂, and ZnO. In still another embodiment, themetal-inorganic composite comprises Au—Ni—TiO₂, Ni—Co—TiO₂, Ni—Zn—Al₂O₃,or Ni—B—TiO₂. The method can further comprise removing non-polymerizedresin. The method can yet further comprise, or alternatively comprise,pyrolizing the sub-micron architectural material to remove organicmaterial. In one embodiment, the pyrolizing comprises a two-steppyrolysis technique to remove organic material followed by removingoxygen. In another embodiment, the sub-micron architectural materialcomprises a metal, a metalloid and/or an inorganic structure having adimension across an axis of a metal, a metalloid and/or an inorganicmaterial strut, beam or joint of less than 1 micron.

The disclosure also provides a device comprising the sub-micronarchitectural material made by a method of the disclosure wherein thedevice comprises a metal, a metalloid, and/or an inorganic scaffold thatis free of organic material having a strut, beam or joint cross axisdimension (e.g., a radial dimension) of less than 1 micron. In oneembodiment, the device device comprises titania. In another embodiment,the device is an electrode, photocell, filter, circuit, waterpurification device or nanocage.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1A-J shows a process for nanoscale additive manufacturing of metalsand SEM characterization of the fabricated samples. (A) Ligand exchangereaction used to synthesize metal precursor with cross-linkingfunctionality. (B) Metal precursor, acrylic resin, and photoinitiatorare mixed to form a transparent metal-containing photoresist. (C)Schematic of two-photon lithography (TPL) process used to sculpt thescaffold. (D) Schematic of fabrication of metal-containing polymer partthat is (E) pyrolized to remove organic content and to convert thepolymer into a metal. SEM images of (F-H) a representative octet latticemade out of a nickel-containing polymer at different magnifications and(I), (J) a representative nickel nanolattice after pyrolysis.Magnifications in (G) and (I) (scale bars 2 μm) and also (H) and (J)(scale bars 500 nm) are identical. Scale bar is 15 μm for (F).

FIG. 2A-H shows Energy Dispersive Spectroscopy (EDS) characterization offabricated metal nanostructures. SEM images of supported 20 μmtetrakaidekahedron unit cell on a Si chip before pyrolysis and (B) thesame structure after pyrolysis (4 μm width). (C) SEM image of thestructure showing where EDS data was collected. (D) EDS spectrum takenwithin the beam of the structure suggests that the chemical compositionis more than 90 wt % nickel. (E-H), EDS maps show high uniformity of theatomic composition throughout the structure. Scale bars are 5 μm for (A)1 μm for (C) and 2 μm for (D) , (E-H).

FIG. 3A-F shows TEM characterization of the resulting metal structure.(A) SEM image of nickel beams fabricated directly on a 200 nm-thick SiNmembrane TEM grid (B) Low-magnification TEM of a 100 nm nickel beamoverhanging the edge of 1.25 μm hole in a SiN membrane. (C) TEM image ofthe metal sample region where the diffraction pattern was taken. (D)Electron diffraction pattern shows that the printed beam consists mostlyout of polycrystalline nickel with a small amount of nickel oxide. (E)HRTEM image of a printed metal beam. Analysis of atomic plane distancesusing FFT shows predominantly polycrystalline nickel (region 1) withsome amount of nickel carbide within the structure (region 2) and nickeloxide at the surface of the structure (region 3). (F) Grain sizehistogram for n=40 particles measured from a TEM image.

FIG. 4A-F shows in-situ uniaxial compression of 3D printed nickel octetnanolattices. (A)-(D), SEM images of the nickel structure during thecompression test a, before full contact, (B) in the elastic regime, (C)during layer-by-layer collapse, and (D) during densification. (E)Stress-strain diagram showing compression of four nickel nanolattices.Letters on the graph correspond to the regions represented by (A)-(D).(F) Specific strength-beam size plot showing properties of nickelnanolattices compared to other metal lattices fabricated using SelectiveLaser Melting (SLM), Direct Metal Laser Sintering (DMLS), Electron BeamMelting (EBM), and ink-based methods. Scale bars are 5 μm for (A)-(D).

FIG. 5 shows a comparison of minimum feature sizes for scalable metaladditive manufacturing technologies. Using metal-containing photoresistallows to fabricate complex 3D geometries with the resolution that is anorder of magnitude finer than that of the state-of-the-art metal AMmethods.

FIG. 6 shows an SEM image of a representative supporting structure usedto decouple the part from the substrate during pyrolysis.

FIG. 7A-C shows a concept of a household solar water disinfectiondevice. (A) Architected self-supported titania is placed inside a PETbottle filled with water in the sunlight. (B) The photocatalyst promotesgeneration of ROS that deactivate microorganisms. The architectureallows for the light to be delivered into the bulk of the photocatalyst,supporting the disinfection throughout the whole volume of the reactor.(C) After disinfection is complete, the water can be consumed rightaway, without the need to filter out the catalyst.

FIG. 8A-E shows a process for AM of titania and SEM characterization ofprinted titania structures. (A) Shows ligand exchange reaction to addacrylic functional groups onto titanium clusters followed by a schematicof the SLA instrument to pattern titanium-containing photoresist intocomplex 3D geometries. Optical images of a cubic lattice made fromtitanium-containing polymer before and after pyrolysis. (B) Top view ofa titania octet lattice (optical image). SEM images of (C) arepresentative node in the unit cell of an octet lattice and (D, E)titania nano-crystallites on the surface of the structure. Scale barsare 5 mm for (A), 2 mm for (B), 100 μm for (C), 5 μm for (D) , and 500nm for (E).

FIG. 9A-F shows EDS and Raman characterization of printed titaniastructures. (A) SEM image of an octet lattice node where EDS maps weretaken. EDS maps show uniform distribution of (B) titanium, (D) oxygen,and (E) carbon within the structure. (C) EDS spectrum taken from one ofthe beams shows mostly titanium and oxygen content by weight. (F) Ramanspectrum of a 3D printed structure compared to reference spectra ofanatase and rutile TiO2 indicates mostly rutile phase of titania. Scalebars are 100 μm for (A), (B), (D), and (E).

FIG. 10A-F shows TEM and SEM characterization of printed titaniastructures. (A) SEM image of a beam cross-section shows that the size oftitania crystals gets smaller closer to the beam center. (B) Histogramshowing distribution of titania particle sizes measured from TEM images.(C) HRTEM image showing titania particles. FFT analysis was used todetermine the orientation and lattice spacings for one of the crystals.(D) Low-magnification TEM image of titania nanoparticles from theprinted structure. (E) TEM image of the area where electron diffractionpattern was taken. (F) Electron diffraction pattern indicates mostlyrutile titania.

FIG. 11A-E shows uniaxial compression test of printed titania cubiclattices. (A-D) Optical images of the structure during uniaxialcompression showing different stages during the compression test:elastic region (A), followed by brittle failure of the first layer (B,C) and gradual brittle failure of individual beams and layers (D). (E)Stress-strain data for three cubic lattices. Scale bars for (A-D) are 5mm.

FIG. 12A-B shows 2D patterning of NiNPs. (A) Grid pattern of NiNPs on Siafter removing the organic content from a lithographically-defined gridstructure. (B) Carbon nanotube (CNT) synthesis using pre-patterned NiNPson Si.

DETAILED DESCRIPTION

As used herein and in the appended claims, the singular forms “a,” “an,”and “the” include plural referents unless the context clearly dictatesotherwise. Thus, for example, reference to “a photoinitiator” includes aplurality of such photoinitiators and reference to “the metal” includesreference to one or more metals, and so forth.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood to one of ordinary skill inthe art to which this disclosure belongs. Although methods and materialssimilar or equivalent to those described herein can be used in thepractice of the disclosed methods and compositions, the exemplarymethods, devices and materials are described herein.

Also, the use of “or” means “and/or” unless stated otherwise. Similarly,“comprise,” “comprises,” “comprising” “include,” “includes,” and“including” are interchangeable and not intended to be limiting.

It is to be further understood that where descriptions of variousembodiments use the term “comprising,” those skilled in the art wouldunderstand that in some specific instances, an embodiment can bealternatively described using language “consisting essentially of” or“consisting of.”

Any publications discussed above and throughout the text are providedsolely for their disclosure prior to the filing date of the presentapplication. Nothing herein is to be construed as an admission that theinventors are not entitled to antedate such disclosure by virtue ofprior disclosure.

Additive manufacturing (AM) represents a set of processes that enablelayer by layer fabrication of complex 3D structures using a wide rangeof materials that include inorganic, hybrid organic-inorganic materials,polymers, and metals. The development of metal AM has revolutionized theproduction of complex parts for aerospace, automotive and medicalapplications. Today's resolution of most commercially available metal AMprocesses is ˜20-50 μm²; no established method is available for printing3D features below these dimensions. It has been shown that uniquephenomena arise in metals with micro- and nano-dimensions, for examplelight trapping in optical meta-materials and enhanced mechanicalresilience. Accessing these phenomena requires developing a process tofabricate 3D metallic architectures with macroscopic overall dimensionsand individual constituents in the sub-micron regime.

Minimum feature size in metal AM is generally limited by the materialfeed, which include metal powder, metal wire, sheet metal, and metalinks. Inkjet-based methods manipulate 40-60 μm droplets of metal inks;wire- and filament-based processes, i.e. Plasma Deposition and ElectronBeam Freeform Fabrication (EBF3), rely on locally melting a >100μm-diameter metal wire; and powder-based processes, i.e. Selective LaserMelting (SLM) and Laser Engineered Net Shaping (LENS), consolidate˜0.3-10 μm metal powder particles. Overcoming these resolutionlimitations requires developing the capability of a material feed tomanipulate nanoscale quantities of metals in a stable and scalable 3Dprinting process. Alternative material feeds to fabricate 3D metalstructures with a <10 μm resolution include nanoparticle inks, ionsolutions, droplets of molten metal, and precursor gases. Methods thatuse localized electroplating or metal ion reduction are capable ofproducing features down to 500 nm using a very slow process that islimited by the electroplating rate. Electrochemical fabrication (EFAB)allows for manufacturing geometries with 10 μm features and 4 μm layersbut is limited to structures with a total height of 25-50 layers. Othertechnologies, like micro-deposition of metal nanoparticle inks or moltenmetal and focused ion beam direct writing (FIBDW), also suffer from slowthroughput and are more suited for low-volume fabrication and repair.

As used herein “framework material” refers to a metal, a metalloid, ametal alloy, a metal oxide, a metal nitride, an inorganic, andinorganic/organic hybrid and/or a carbon-based material that is presentin a photoresist resin of the disclosure and that upon polymerizationremains as part of a framework or structure. Moreover, in someinstances, the framework-material remains as part of, or the onlyremaining component of, the framework or structure following heattreatment (e.g., pyrolization). In some embodiment, theframework-material comprises, but is not limited to, a metal ion thatbridges 2 or more monomeric ligand units comprising photopolymerizablegroups.

This disclosure provides a scalable and reproducible process to createcomplex 3D metal geometries with sub-micron (i.e., less than 1 μm, forexample, 5-999 nm or any value there between) up to 50 μm (and anyinteger size there between) features by applying lithographic methods tometal-, inorganic-, and hybrid inorganic/organic-rich polymer resins.

The disclosure provides a photopolymerizable resist comprising a metal,a metalloid, a metal alloy, a metal oxide, a metal nitride, aninorganic, and inorganic/organic hybrid and/or a carbon-based material(the “framework-material”). The photopolymerizable resist comprises (i)a hybrid organic-inorganic polymer resin comprising a metal, ametalloid, a metal alloy, a metal oxide, a metal nitride, an inorganic,and inorganic/organic hybrid and/or a carbon-based material (“M”) thatare part of a monomeric ligand unit or that bridge at least twomonomeric ligand units “L”, e.g., L-M-L, (ii) a photoinitiator, and(iii) a reactable monomer.

The photopolymerizable organic-inorganic resin can be made by reacting amonodentate, bidentate or weak framework-material exchange ligand withat least one monomeric ligand unit. For example, the weakframework-material exchange ligand has the general structure:(L⁻)^(n)M^(n+), where L⁻ is a negatively charged ligand, n is 1, 2, 3,4, 5 or 6 and M is a metal, a metal, a metalloid, a metal alloy, a metaloxide, a metal nitride, an inorganic, and inorganic/organic hybridand/or a carbon-based material cation.

The monomeric ligand unit generally comprises the structure:

wherein R is an alkene or a C₂₋₁₀ terminal alkene and R′ is N, O, F, Sor Cl. In one embodiment, the monomeric ligand unit is an acryloyl. Inanother embodiment, the monomeric ligand unit comprises a carboxylicacid and an alkene, e.g., C═R—COOH, wherein R is 1-10 carbons. A generalscheme for producing a hybrid organic-inorganic polymer resin isprovided in Scheme I:

wherein “M” is a metal, a metal ion, a metalloid, a metal alloy, a metaloxide, a metal nitride, an inorganic, an inorganic/organic hybrid and/ora carbon-based material. In one embodiment, the metal or metal ionincludes, but is not limited to, Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺, Be²⁺, Mg²⁺,Ca²⁺, Sr²⁺, Ba²⁺, Sc³⁺, Sc²⁺, Sc⁺, Y³⁺, Y²⁺, Y⁺, Ti⁴⁺, Ti³⁺, Ti²⁺, Zr⁴⁺,Zr³⁺, Zr²⁺, Hf⁴⁺, Hf³⁺, V⁵⁺, V⁴⁺, V³⁺, V²⁺, Nb⁵⁺, Nb⁴⁺, Nb³⁺, Nb²⁺,Ta⁵⁺, Ta⁴⁺, Ta³⁺, Ta²⁺, Cr⁶⁺, Cr⁵⁺, Cr⁴⁺, Cr³⁺, Cr²⁺, Cr⁺, Cr, Mo⁶⁺,Mo⁵⁺, Mo⁴⁺, Mo³⁺, Mo²⁺, Mo⁺, Mo, W⁶⁺, W⁵⁺, W⁴⁺, W³⁺, W²⁺, W⁺, W, Mn⁷⁺,Mn⁶⁺, Mn⁵⁺, Mn⁴⁺, Mn³⁺, Mn²⁺, Mn⁺, Re⁷⁺, Re⁶⁺, Re⁵⁺, Re⁴⁺, Re³⁺, Re²⁺,Re⁺, Re, Fe⁶⁺, Fe⁴⁺, Fe³⁺, Fe²⁺, Fe⁺, Fe, Ru⁸⁺, Ru⁷⁺, Ru⁶⁺, Ru⁴⁺, Ru³⁺,Ru²⁺, Os⁸⁺, Os⁷⁺, Os⁶⁺, Os⁵⁺, Os⁴⁺, Os³⁺, Os²⁺, Os⁺, Os, Co⁵⁺, Co⁴⁺,Co³⁺, Co²⁺, Co⁺, Rh⁶⁺, Rh⁵⁺, Rh⁴⁺, Rh³⁺, Rh²⁺, Rh⁺, Ir⁶⁺, Ir⁵⁺, Ir⁴⁺,Ir³⁺, Ir²⁺, Ir⁺, Ir, Ni³⁺, Ni²⁺, Ni⁺, Ni, Pd⁶⁺, Pd⁴⁺, Pd²⁺, Pd⁺, Pd,Pt⁶⁺, Pt⁵⁺, Pt⁴⁺, Pt³⁺, Pt²⁺, Pt⁺, Cu⁴⁺, Cu³⁺, Cu²⁺, Cu⁺, Ag³⁺, Ag²⁺,Ag⁺, Au⁵⁺, Au⁴⁺, Au³⁺, Au²⁺, Au⁺, Zn²⁺, Zn⁺, Zn, Cd²⁺, Cd⁺, Hg⁴⁺, Hg²⁺,Hg⁺, B³⁺, B²⁺, B⁺, Al³⁺, Al²⁺, Al⁺, Ga³⁺, Ga²⁺, Ga⁺, In³⁺, In²⁺, In¹⁺,Tl³⁺, Tl⁺, Si⁴⁺, Si³⁺, Si²⁺, Si⁺, Ge⁴⁺, Ge³⁺, Ge²⁺, Ge⁺, Ge, Sn⁴⁺, Sn²⁺,Pb⁴⁺, Pb²⁺, As⁵⁺, As³⁺, As²⁺, As⁺, Sb⁵⁺, Sb³⁺, Bi⁵⁺, Bi³⁺, Te⁶⁺, Te⁵⁺,Te⁴⁺, Te²⁺, La³⁺, La²⁺, Ce⁴⁺, Ce³⁺, Ce²⁺, Pr⁴⁺, Pr³⁺, Pr²⁺, Nd³⁺, Nd²⁺,Sm³⁺, Sm²⁺, Eu³⁺, Eu²⁺, Gd³⁺, Gd²⁺, Gd⁺, Tb⁴⁺, Tb³⁺, Tb²⁺, Tb⁺, Db³⁺,Db²⁺, Ho³⁺, Er³⁺, Tm⁴⁺, Tm³⁺, Tm²⁺, Yb³⁺, Yb²⁺, Lu³⁺ and alloys of anyof the foregoing. In another embodiment, M is one or more metals ormetal ions selected from the group comprising Li⁺, Mg²⁺, Ca²⁺, Ba²⁺,Zr⁴⁺, Zr³⁺, Zr²⁺, Mn³⁺, Mn²⁺, Mn⁺, Fe³⁺, Fe²⁺, Fe⁺, Ni³⁺, Ni²⁺, Ni⁺, Ni,Cu⁴⁺, Cu³⁺, Cu²⁺, Cu⁺, V⁵⁺, V⁴⁺, V³⁺, V²⁺, Co³⁺, Co²⁺, Co⁺, Zn²⁺, Zn⁺,Ce⁴⁺, Ce³⁺, and Ce²⁺ or alloys of any of the foregoing. In yet anotherembodiment, M is one or more metal ions selected from the groupcomprising Li⁺, Mg²⁺, Ca²⁺, Ba²⁺, Zr²⁺, Mn², Fe²⁺, Ni²⁺, Cu²⁺, V²⁺,Co²⁺, Zn²⁺, and Ce²⁺. In a further embodiment, M is Ni²⁺ or Co²⁺ metalions. The inorganic can be a single or mixed oxide, carbide, nitride,silicate, boride of Ti, W, Si, Zr, Al, Y, Cr, Fe, Pb, Co, or a rareearth element. For example, the inorganic can include, but is notlimited to, TiO₂, AlO₂, AlO₃, ZrO₂, SiC, SiO₂, SiC, CeO₂, or ZnO. Asuitable metal-inorganic composite includes, but is not limited to,metal-inorganic composite coating comprises Au—Ni—TiO₂, Ni—Co—TiO₂,Ni—Zn—Al₂O₃, or Ni—B—TiO₂.

Suitable monodentate, bidentate or weak exchange ligands (“L⁻”) include,e.g., various alkoxides. Examples of weak framework-material exchangeligand (e.g., (L⁻)_(n)M) are selected from the group consisting ofaluminum triethoxide, aluminum isopropoxide, aluminum sec-butoxide,aluminum tri-t-butoxide, magnesium trifluoroacetylacetonate, magnesiummethoxide, magnesium ethoxide, titanium methoxide, titanium ethoxide,titanium isopropoxide, titanium propoxide, titanium butoxide, titaniumethylhexoxide, titanium (triethanolaminato) isopropoxide, titanium bis(ethyl acetoacetato) diisopropoxide, titanium bis(2,4-pentanedionate)diisopropoxide, zirconium ethoxide, zirconiumisopropoxide, zirconium propoxide, zirconium sec-butoxide, zirconiumt-butoxide, aluminum, di-s-butoxide ethylacetonate, calciummethoxyethoxide, calcium methoxide, magnesium methoxyethoxide, copperethoxide, copper methoxyethoxyethoxide, antimony butoxide, bismuthpentoxide, chromium isopropoxide, tin ethoxide, zinc methoxyethoxide,titanium n-nonyloxide, vanadium tri-n-propoxide oxide, vanadiumtriisobutoxide oxide, iron ethoxide, tungsten ethoxide, samariumisopropoxide, lanthanium methoxyethoxide, cerium(IV)2-methoxethoxide,lanthanium (III) 2-methoxethoxide, Yttrium 2-methoxethoxide, and calcium2-methoxethoxide.

In one embodiment, the reaction of scheme I provides a hybridorganic-inorganic polymer resin that comprises a metal diacrylate, metaltriacrylate or 2 or more acrylate monomers bridged or coordinated by ametal, a metalloid, a metal alloy, a metal oxide, a metal nitride, aninorganic, and inorganic/organic hybrid and/or a carbon-based material.For example, the hybrid organic-inorganic polymer resin can have thegeneral structure (C═R_(m)H_(2m+1)COR′)_(n)M^(n+) wherein m is anyinteger between, and including, 1 and 10, n is an integer between 1 and6, wherein R is a C₁₋₁₀ alkane and R′ is N, O, F, S or Cl. In oneembodiment, the a hybrid organic-inorganic polymer resin has the formulaC═R—COR′-M²⁺—R′OC—R═C, wherein M is a divalent metal ion. In oneembodiment, the divalent ion is a divalent metal ion selected from thegroup consisting of Be²⁺, Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺, Sc²⁺, Y²⁺, Ti²⁺, Zr²⁺,V²⁺, Nb²⁺, Ta²⁺, Cr²⁺, Mo²⁺, W²⁺, Mn²⁺, Re²⁺, Fe²⁺, Ru²⁺, Os²⁺, Co²⁺,Rh²⁺, Ir²⁺, Ni²⁺, Pd²⁺, Pt²⁺, Cu²⁺, Ag²⁺, Au²⁺, Zn²⁺, Cd²⁺, B²⁺, Al²⁺,Ga²⁺, Sn²⁺, Pb²⁺, Hg²⁺, As²⁺, Te²⁺, La²⁺, Ce²⁺, Pr²⁺, Sm²⁺, Gd²⁺, Nd²⁺,Db²⁺, Tb²⁺, Tm²⁺ and Yb²⁺.

FIG. 1A depicts an exemplary reaction between (i) a weakframework-material ligand (e.g., methoxyethoxide) bound to nickel and(ii) acrylic acid as the monomeric ligand unit to yield the hybridorganic-inorganic polymer resin, nickel acrylate.

The disclosure further provides a method of making a photopolymerizableframework-material photoresist. The method comprises mixing (i) a hybridorganic-inorganic polymer resin (e.g., “metal precursor” nickelacrylate; see FIG. 1A) with (ii) a monomer comprising a photochemicalpolymerizable group that allows for propagating carbon or nitrogenchains and (iii) a photoinitiator.

The photoinitiator used in the photopolymerizable resist mixture causesa radical reaction or ion reaction in response to contact by light.There are a number of photoinitiators known in the art. For example,suitable photoinitiators include, but are not limited to,7-diethylamino-2-coumarin, acetophenone, p-tert-butyltrichloroacetophenone, chloro acetophenone, 2-2-diethoxy acetophenone, hydroxyacetophenone, 2,2-dimethoxy-2′-phenyl acetophenone, 2-aminoacetophenone, dialkylamino acetophenone, benzyl, benzoin, benzoin methylether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutylether, 1-hydroxycyclohexyl phenyl ketone,2-hydroxy-2-methyl-1-phenyl-2-methylpropane-1-one,1-(4-isopropylphenyl)-2-hydroxy-2-methylpropane-1-one, benzyl dimethylketal, benzophenone, benzoylbenzoic acid, methyl benzoyl benzoate,methyl-o-benzoyl benzoate, 4-phenyl benzophenone, hydroxy benzophenone,hydroxypropyl benzophenone, acrylic benzophenone,4-4′-bis(dimethylamino)benzophenone, perfluoro benzophenone,thioxanthone, 2-chloro thioxanthone, 2-methyl thioxanthone, diethylthioxanthone, dimethyl thioxanthone, 2-methyl anthraquinone, 2-ethylanthraquinone, 2-tert-butyl anthraquinone, 1-chloro anthraquinone,2-amyl anthraquinone, acetophenone dimethyl ketal, benzyl dimethylketal, α-acyl oxime ester, benzyl-(o-ethoxycarbonyl)-α-monoxime, acylphosphine oxide, glyoxy ester, 3-keto coumarin, 2-ethyl anthraquinone,camphor quinone, tetramethylthiuram sulfide, azo bis isobutyl nitrile,benzoyl peroxide, dialkyl peroxide, tert-butyl peroxy pivalate,perfluoro tert-butyl peroxide, perfluoro benzoyl peroxide, etc. Further,it is possible to use these photoinitiator alone or in combination oftwo or more. Other photoinitiators will be known in the art.

The monomer of the monomeric ligand unit can be any momomeric compoundhaving an activatable photopolymerizable group that can propagate carbonor nitrogen bond formation. In one embodiment, the monomer ispolymerized to form a polyacrylate such as polymethylmethacrylate, anunsaturated polyester, a saturated polyester, a polyolefin(polyethylenes, polypropylenes, polybutylenes, and the like), an alkydresin, an epoxy polymer, a polyamide, a polyimide, a polyetherimide, apolyamideimide, a polyesterimide, a polyesteramideimide, polyurethanes,polycarbonates, polystyrenes, polyphenols, polyvinylesters,polysilicones, polyacetals, cellulose acetates, polyvinylchlorides,polyvinylacetates, polyvinyl alcohols polysulfones, polyphenylsulfones,polyethersulfones, polyketones, polyetherketones, poyletheretherketones,polybenzimidazoles, polybemzoxazoles, polybenzthiazoles,polyfluorocarbones, polyphenylene ethers, polyarylates, cyanate esterpolymers, copolymers of two or more thereof, and the like.

Examples of acrylic monomers include monoacrylics, diacrylics,triacrylics, tetraacrylics, pentacrylics, etc. Examples of polyacrylatesinclude polyisobornylacrylate, polyisobornylmethacrylate,polyethoxyethoxyethyl acrylate, poly-2-carboxyethylacrylate,polyethylhexylacrylate, poly-2-hydroxyethylacrylate,poly-2-phenoxylethylacrylate, poly-2-phenoxyethylmethacrylate,poly-2-ethylbutylmethacrylate, poly-9-anthracenylmethylmethacrylate,poly-4-chlorophenylacrylate, polycyclohexylacrylate,polydicyclopentenyloxyethyl acrylate, poly-2-(N,N-diethylamino)ethylmethacrylate, poly-dimethylaminoeopentyl acrylate, poly-caprolactone2-(methacryloxy)ethylester, and polyfurfurylmethacrylate, poly(ethyleneglycol)methacrylate, polyacrylic acid and poly(propylene glycol)methacrylate.

Examples of suitable diacrylates which can be used to form polyacrylatesinclude 2,2-bis(4-methacryloxyphenyl)propane, 1,2-butanediol diacrylate,1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate,1,4-cyclohexanediol dimethacrylate, 1,10-decanediol dimethacrylate,diethylene glycol diacrylate, dipropylene glycol diacrylate,dimethylpropanediol dimethacrylate, triethylene glycol dimethacrylate,tetraethylene glycol dimethacrylate, 1,6-hexanediol diacrylate,neopentyl glycol diacrylate, polyethylene glycol dimethacrylate,tripropylene glycol diacrylate,2,2-bis[4-(2-acryloxyetho-xy)phenyl]propane,2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy)phenyl]propane,bis(2-methacryloxyethyl)N,N-1, 9-nonylene biscarbamate,1,4-cycloheanedimethanol dimethacrylate, and diacrylic urethaneoligomers (reaction products of isocyanate terminate polyol and2-hydroethylacrylate). Examples of triacrylates which can be used toform polyacrylates include tris(2-hydroxyethyl)isocyanuratetrimethacrylate, tris(2-hydroxyethyl)isocyanurate triacrylate,trimethylolpropane trimethacrylate, trimethylolpropane triacrylate andpentaerythritol triacrylate. Examples of tetracrylates includepentaerythritol tetraacrylate, di-trimethylopropane tetraacrylate, andethoxylated pentaerythritol tetraacrylate. Examples of pentaacrylatesinclude dipentaerythritol pentaacrylate and pentaacrylate ester.

As mentioned above the hybrid organic-inorganic polymer resin is notlimited. The hybrid organic-inorganic polymer resin used in thephotopolymerizable resist is not limited so long as the hybridorganic-inorganic polymer resin comprises a polymerizable monomer. Suchpolymerizable groups on the hybrid organic-inorganic polymer resintypically have acryloyl group or a methacryloyl group, monomers having avinyl group, and monomers having an allyl group. Further, the hybridorganic-inorganic polymer resin will typically be polyfunctionalmonomers comprising a plurality of polymerizable groups, and the numberof polymerizable groups comprises an integer of from 1 to 4. Examples anacryloyl group or a methacryloyl group useful in a hybridorganic-inorganic polymer resin are (meth)acrylic acids; aromatic(meth)acrylates such as phenoxyethyl acrylate, benzyl acrylate, etc.;hydrocarbon (meth)acrylates such as stearyl acrylate, lauryl acrylate,2-ethylhexyl acrylate, allyl acrylate, 1,3-butanediol diacrylate,1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, trimethylolpropanetriacrylate, pentaerythritol triacrylate, dipentaerythritolhexaacrylate, etc.; ethereal oxygen atom-containing hydrocarbon(meth)acrylates such as ethoxyethyl acrylate, methoxyethyl acrylate,glycidyl acrylate, tetrahydrofurfuryl acrylate, diethylene glycoldiacrylate, neopentylglycol diacrylate, polyoxyethylene glycoldiacrylate, tripropylene glycol diacrylate, etc.

After the photopolymerizable framework-material photoresist has beenprepared, it can be stored under appropriate conditions (depending uponthe components, e.g., under inert gas and typically in the dark). Thephotopolymerizable framework-material photoresist can be applied to asubstrate by spin, drop cast, dip coating or any other commonly usedmethods. In some embodiments, the method can utilize a technique tocarefully control the amount, thickness or layering of thephotopolymerizable framework-material photoresist. Thephotopolymerizable framework-material photoresist can be drop cast ordeposited on a substrate at any appropriate thickness evenly orunevenly. The substrate is not limiting and can be any of a glass, apolymer, a ceramic, an inorganic, an alumina, a stainless steel, atitanium and a semiconductive substrate.

The photopolymerizable framework-material photoresist is then exposed toone or more beams of photons/light to initiate free radical productionby the photoinitiator and to polymerize the monomers to produce apolymeric material containing a framework-material. In one embodiment,the method uses a two photon lithography (TPL) technique. Two photonlithography allows for the penetration of the photopolymerizableframework-material photoresist by the individual photon beams which areindividually insufficient to cause polymerization until both contact aphotopolymerizable location. Under TPL, each of the photon beamsprovides one-half the energy required to cause photoinitiation and thuspolymerization. Thus, a 3D structures can be fabricated using apolymerizable system that requires two photons to simultaneously impingeon a photopolymerizable material. The two photons can be dimensionallytargeted (e.g., by mirrors) or may be temporally targeted (e.g., pulsedlasers). Local activation of the photopolymerizable framework-materialphotoresist occurs by simultaneous absorption of the two photons.Typically, the wavelengths are in the near-infrared region.

After polymerization of a desires structure comprising aframework-material, non-polymerized monomers and reagents are washedaway. The remaining structure can then be dried or pyrolized to removeany remaining organic material. The resulting structure comprises analmost entirely metal-, inorganic-, carbon-, oxide-, nitride and/orcarbon-based structure.

In any of the foregoing paragraphs, the term “framework-material” can bereplaced with the term “metal” and/or “metal ion”. For example, the term“framework-material” can be replaced with any of Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺,Be²⁺, Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺, Sc³⁺, Sc²⁺, Sc⁺, Y³⁺, Y²⁺, Y⁺, Ti⁴⁺, Ti³⁺,Ti²⁺, Zr⁴⁺, Zr³⁺, Zr²⁺, Hf⁴⁺, Hf³⁺, V⁵⁺, V⁴⁺, V³⁺, V²⁺, Nb⁵⁺, Nb⁴⁺,Nb³⁺, Nb²⁺, Ta⁵⁺, Ta⁴⁺, Ta³⁺, Ta²⁺, Cr⁶⁺, Cr⁵⁺, Cr⁴⁺, Cr³⁺, Cr²⁺, Cr⁺,Cr, Mo⁶⁺, Mo⁵⁺, Mo⁴⁺, Mo³⁺, Mo²⁺, Mo⁺, Mo, W⁶⁺, W⁵⁺, W⁴⁺, W³⁺, W²⁺, W⁺,W, Mn⁷⁺, Mn⁶⁺, Mn⁵⁺, Mn⁴⁺, Mn³⁺, Mn²⁺, Mn⁺, Re⁷⁺, Re⁶⁺, Re⁵⁺, Re⁴⁺,Re³⁺, Re²⁺, Re⁺, Re, Fe⁶⁺, Fe⁴⁺, Fe³⁺, Fe²⁺, Fe⁺, Fe, Ru⁸⁺, Ru⁷⁺, Ru⁶⁺,Ru⁴⁺, Ru³⁺, Ru²⁺, Os⁸⁺, Os⁷⁺, Os⁶⁺, Os⁵⁺, Os⁴⁺, Os³⁺, Os²⁺, Os⁺, Os,Co⁵⁺, Co⁴⁺, Co³⁺, Co²⁺, Co⁺, Rh⁶⁺, Rh⁵⁺, Rh⁴⁺, Rh³⁺, Rh²⁺, Rh⁺, Ir⁶⁺,Ir⁵⁺, Ir⁴⁺, Ir³⁺, Ir²⁺, Ir⁺, Ir, Ni³⁺, Ni²⁺, Ni⁺, Ni, Pd⁶⁺, Pd⁴⁺, Pd²⁺,Pd⁺, Pd, Pt⁶⁺, Pt⁵⁺, Pt⁴⁺, Pt³⁺, Pt²⁺, Pt⁺, Cu⁴⁺, Cu³⁺, Cu²⁺, Cu⁺, Ag³⁺,Ag²⁺, Ag⁺, Au⁵⁺, Au⁴⁺, Au³⁺, Au²⁺, Au⁺, Zn²⁺, Zn⁺, Zn, Cd²⁺, Cd⁺, Hg⁴⁺,Hg²⁺, Hg⁺, B³⁺, B²⁺, B⁺, Al³⁺, Al²⁺, Al⁺, Ga³⁺, Ga²⁺, Ga⁺, In³⁺, In²⁺,In¹⁺, Tl³⁺, Tl⁺, Si⁴⁺, Si³⁺, Si²⁺, Si⁺, Ge⁴⁺, Ge³⁺, Ge²⁺, Ge⁺, Ge, Sn⁴⁺,Sn²⁺, Pb⁴⁺, Pb²⁺, As⁵⁺, As³⁺, As²⁺, As⁺, Sb⁵⁺, Sb³⁺, Bi⁵⁺, Bi³⁺, Te⁶⁺,Te⁵⁺, Te⁴⁺, Te²⁺, La³⁺, La²⁺, Ce⁴⁺, Ce³⁺, Ce²⁺, Pr⁴⁺, Pr³⁺, Pr²⁺, Nd³⁺,Nd²⁺, Sm³⁺, Sm²⁺, Eu³⁺, Eu²⁺, Gd³⁺, Gd²⁺, Gd⁺, Tb⁴⁺, Tb³⁺, Tb²⁺, Tb⁺,Db³⁺, Db²⁺, Ho³⁺, Er³⁺, Tm⁴⁺, Tm³⁺, Tm²⁺, Yb³⁺, Yb²⁺ and Lu³⁺. In oneembodiment, the framework material is a divalent metal ion.

Although any number of materials can be used in the methods andcompositions (as described above) , the disclosure exemplifies themethods of the disclosure using, in one embodiment, nickel acrylate madeby a ligand exchange reaction between nickel alkoxide and acrylic acid(FIG. 1A) and then combining it with another acrylic monomer,pentaerythritol triacrylate, and a photoinitiator (PI) ,7-diethylamino-3-thenoylcoumarin, (FIG. 1B). The photoresist is thenapplied (e.g., by drop casting) to a substrate (e.g., a siliconsubstrate) and two-photon lithography (TPL) is used to sculpt a desired3D architecture (FIG. 1C). The non-polymerized resist was then washedaway, and the free-standing cross-linked polymer nano- and/ormicro-architectures were then heat processed. The heat processing can beused to further catalyze the conversion of a framework-material (e.g.,carbon to graphene) or to remove volatile material. For example, thenano- and/or micro-architectured structure is pyrolyzed to volatilizethe organic content. This process yielded a ˜80% smaller replica of theoriginal 3D structure made entirely out of metal (FIG. 1D).

Pyrolysis can be performed in a one- or multi-step process. For example,in one embodiment, a two-step process is used that includes performingpyrolysis in a furnace at about 600-1000° C. to remove organic contentand to consolidate metal and/or inorganic features followed by a lowertemperature heat processing of about 200-600° C. to reduce the oxygencontent.

The disclosure provides a feasible and efficient method of fabricating ametal, a metalloid, a metal alloy, a metal oxide, a metal nitride, aninorganic, a hybrid inorganic-organic and/or a carbon-based materialnano- and/or micro-structures. For example, the methods of thedisclosure produced nanolattices with 10 μm octet unit cells comprisedof 2 μm-diameter circular beams out of the synthesizedphotopolymerizable framework-material photoresist using layer-by-layerTPL with 150 nm layer thickness. SEM images in FIG. 1F-H reveal thatthese nanolattices had fully dense beams and uniformly sized,high-fidelity features. These nanolattices had four unit cells on eachside, 40 μm, and a height of three unit cells, 30 μm, and were supportedby vertical springs at each corner and by a vertical pillar the center.These supports served as pedestals that would allow the sample torelease from substrate after undergoing an isotropic ˜80% shrinkageduring pyrolysis (see FIG. 6).

The disclosure thus, provides an additive manufacturing (AM) process tocreate 3D nano- and micro-architected metal, metalloid, metal alloy,metal oxide, metal nitride, inorganic, inorganic-organic hybrid and/orcarbon-based materials using a scalable lithography-based approach.

As exemplified below, the process produced Ni octet-lattices with 2 μmunit cells, 300-400 nm beams and 30 nm layers. The resolution of themethod of the disclosure allows printing metal features with 25-100 nmdimensions, which is an order of magnitude smaller than feature sizesproduced using all other 3D-capable metal AM methods. Lateral featuresizes of complex 3D architectures fabricated using this process can befurther refined to 24 nm. This nanoscale metal AM method is not limitedto nickel as exemplified below, but can be applied to otherorganometallics as described elsewhere herein and can be used to deriveUV-curable metal-based photoresists using similar chemical synthesis.Successful fabrication of nickel 3D nano-structures demonstrates thatthis approach can be applied to print sophisticated metallicarchitectures that are challenging to 3D print using established metalAM processes, e.g. molybdenum and tungsten. Nanoscale additivemanufacturing of metals has direct implications and open opportunitiesfor scalable production of complex sub-millimeter devices, including 3DMEMS, 3D microbattery electrodes, and microrobots and tools forminimally invasive medical procedures.

For example, the methods of the disclosure allow for the generation ofmetal, metalloid, metal alloy, metal oxide, metal nitride, inorganic,inorganic-organic hybrid and/or carbon-based nanostructures that providehigh surface areas. This is important in various applications thatutilize various metal and/or inorganic properties.

Solar disinfection of drinking water (SODIS) is an approach for waterpurification widely used in households with limited access to freshwater. SODIS relies on microorganism inactivation triggered by sunlightenergy in the UV spectrum and requires processing times of up to 48 hr.Water treatment rate is drastically increased by using photocatalyticmaterials, such as TiO₂, which can harvest sunlight to promotegeneration of reactive oxygen species (ROS) that inactivate bacteriawithin few hours. One main challenge that impedes the insertion ofphotocatalysts in most water treatment approaches is the need topopulate the catalyst particles on a three-dimensional (3D) structurewith a high-surface area that is stable under water flow.

The disclosure demonstrates that the method of the disclosure can beutilized to fabricate an architectured TiO₂ device that does not requireexpensive filtering of the catalyst. The TiO₂ device was fabricatedusing the additive manufacturing (AM) method of the disclosure and usingtitania as the framework-material. As described above, a weak ligand wasused to create a titanium monomers via a ligand exchange reactionbetween titanium alkoxide and acrylic acid and utilize the titaniummonomers to prepare a photopolymerizable titania photoresist. Thisphotoresist was then used in a commercial stereolithography apparatus todefine complex 3D architectures, which was then pyrolyzed to removeorganic content. The resulting structure has ˜40% reduced dimensionscompared with its as-fabricated counterpart and has a chemicalcomposition of 46 wt % Ti, 31 wt % O, and 23 wt % C, as measured at thesurface by Energy-Dispersive Spectroscopy (EDS). Using this methodology,3D structures were fabricated with periodic cubic and octet geometrieswhose unit cells range from 0.65 to 1.14 mm, beam lengths of 115-170 μm,and relative densities of 11-31%. Transmission Electron Microscopy (TEM)analysis reveals the microstructure of these lattices is nanocrystallinetitania (rutile) with a mean grain size of ˜60 nm. Mechanicalexperiments reveal that these cubic titania microlattices, whose densityis 350-365 kg/m³, achieve compressive strengths of up to 4.3 MPa, whichis several times stronger than what is reported for titania foams withcomparable density.

As an exemplary embodiment, the disclosure provides a water disinfectiondevice made by the methods of the disclosure. A rendition of anarchitected titania device for household solar water disinfection isshown in FIG. 7. A three-dimensional titania scaffold (30) (as describedabove) is placed inside of an optically transparent (e.g., PET) filledwater bottle (20) and placed in the sunlight (10) (FIG. 7A). The lightinteracts with the titania photocatalyst in the titania scaffold (30),which promotes the reaction with water and dissolved oxygen to producehydroxyl (.OH) and superoxide radicals (.O2-) that deactivate bacteria(FIG. 7B). The designed open-cell architecture of the scaffold allowsthe light to propagate throughout the photocatalyst volume, whichpromotes the generation of ROS throughout the entire liquid volume andefficiently disinfects the water. High strength of the architectedstructure ensures that the catalytic material is not released to thetreated water, so that it can be readily consumed after the disinfection(FIG. 7C).

The foregoing embodiment further demonstrates that various metals,metalloids and/or inorganics can be used in the methods and compositionsof the disclosure. Moreover, that the titania AM process can be used tocreate safe, efficient and cost-effective photocatalytic reactors forhousehold water disinfection, as well as for applications inphotocatalytic hydrogen production, CO₂ conversion, and tissueengineering.

Outstanding electrical and optical properties of graphene,sp2-hybridized planar allotrope of carbon, have made it highlyattractive for transparent conductive films (TCFs) and energystorage/conversion device applications. Transferring the desiredproperties of graphene onto non-planar devices requires methods fordefining the net shape of graphene architectures, such as 3D printing.The existing methods for AM of graphene-containing materials implyeither low graphene/graphene oxide (G/GO) loading of resins forstereolithography or using low-resolution extrusion-based techniques formaterial deposition. These considerations limit graphene AM either tostructures with low graphene content or to at most 100 μm resolution.

Using the methods described herein an AM process for graphene foams isprovided. For example, an AM of graphene foams with critical dimensionsin the nano-scale regime. This embodiment, includes (i) defining a 3Dstructure using a hybrid organic-inorganic chemical that containsinorganic nickel clusters branched with functional groups that allow forphotopolymerization and (ii) pyrolyzing the structure to achievecatalytic conversion of carbon to graphene. As described herein aboveand in Example 1, below, nickel-containing acrylic resin can be mixedwith a photoinitiator to form a catalyst-containing photoresist. 3Dstructure made of catalyst-containing polymer can then be defined usinglithographic methods. The structure can be further pyrolyzed leading tonickel-catalyzed conversion solid-source carbon to sp2-hybridized form,effectively defining a G/GO 3D structure.

The method includes (i) preparing a nickel photoresist (as describedherein), (ii) defining a 3D structure with micron- or submicron-sizedfeatures made of the Ni photoresist using two-photon lithography, and(iii) pyrolyzing the resulting structure in forming gas to yield a 3Dprinted nickel/G/GO structure with 400 nm features.

AM of G/GO aerogel structures is accomplished using alternative3D-printing methods, e.g. micro-SL, SL, etc. Furthermore, carbonnanotube (CNT) structures may be fabricated via catalytic conversion ofsolid source carbon in the 3D polymer structure using incorporated ironor nickel NPs. Additionally, graphene foams may be architected todecouple electrical and optical properties for TCEs. Graphene structurescan be fabricated to have a smaller footprint, yielding a moretransparent film. At the same time, more interconnects can be added tothe architected graphene film structure, which may decrease the sheetresistance of the film.

In another aspect, a metal alkoxide-derived acrylic resin can be usedfor patterning of catalytic particles to enable nano-scale spatialcontrol of chemical processes. In this embodiment, a 2D pattern of metalcatalyst-containing resin can be defined on a substrate usinglithography. Then the organic content of the structure can be removed(e.g., using thermal processing), which leaves a pattern of metalnanoparticles (NPs). Metal NP size distribution can be controlled viametal content of the resin and geometrical parameters of the pattern(e.g. line width and line thickness). These NPs can be further used tolocally catalyze a chemical process, such as catalytic synthesis ofnanomaterials.

EXAMPLES Example 1

UV-curable metal-based photoresist. Acrylic acid (anhydrous, 99%),propylene glycol monomethyl ether acetate (PGMEA) (>99.5%),dichloromethane (anhydrous, ≥99.8%), 2-methoxyethanol (anhydrous,99.8%), and isopropyl alcohol (IPA) (99.7%) were purchased from SigmaAldrich. Nickel 2-methoxyethoxide, 5% w/v in 2-methoxyethanol waspurchased from Alfa Aesar, and 7-diethylamino-3-thenoylcoumarin waspurchased from Exciton. Acrylic acid (100 mg) was slowly added to nickel2-methoxyethoxide solution (1290 mg) in a glove box and manuallyagitated. Nearly immediately a change of the solution color from brownto green was observed, which is indicative of a ligand exchangereaction. The mixture was held at low pressure in the antechamber of theglove box for 45 min to remove ˜60% of 2-methoxyethanol. The resultingprecursor was then taken out of the glove box, mixed with 300 mg ofpentaerythritol triacrylate, and agitated using a vortex mixer for 1min. 7-diethylamino-3-thenoylcoumarin (23 mg) was dissolved in 100 mg ofdichloromethane, added to the mixture, which was then agitated using avortex mixer for 1 min.

Two-photon lithography. Metal-containing polymer structures werefabricated on a silicon chip (1×1 cm) using a commercially availabletwo-photon lithography system (Photonic Professional GT, NanoscribeGmbH). Metal-containing photoresist was drop cast on a glass slide (0.17mm thick, 30 mm in diameter) and confined between the glass slide and asilicon chip using 100 μm thick, 2×10 mm ribbons of Kapton tape asspacers. Laser power and scan speeds were set at 17.5-22.5 mW and 4-6 mms⁻¹, respectively. After the printing process, the samples weredeveloped in 2-methoxyethanol for 1 hour, followed by immersion in PGMEAfor 10 min and filtered IPA for 5 min. The samples were then processedin a critical point dryer (Autosamdri-931).

Pyrolysis. Pyrolysis of the cross-linked metal-containing structures wasconducted in two steps in a quartz tube furnace using 4″ quartz tube. Asthe first step, a heating profile of 2° C./min to 1000° C., hold at1000° C. for 1 hour was applied under 1 L/min argon flow, and the partwas let to cool down in the furnace to room temperature. During thesecond step the part was heated at 2° C./min to 600° C. under 1 L/minforming gas flow (5% H₂, 95% N₂), held at 600° C. for 1 hour, and let tocool down to room temperature. No additional processing was performedafter pyrolysis.

Material characterization. Scanning Electron Microscopy (SEM) imageswere obtained using an FEI Versa 3D DualBeam. SEM Energy-DispersiveX-Ray Spectroscopy (EDS) characterization was performed using a Zeiss1550VP FESEM equipped with an Oxford X-Max SDD system using 10 kVelectron beam.

Transmission Electron Microscopy (TEM) and TEM EDS were performed usingFEI Tecnai F30ST (300 kV) transmission electron microscope equipped withOxford ultra-thin window EDS detector. TEM sample was prepared byfabricating metal structures directly on PELCO Holey Silicon NitrideSupport Film for TEM with 1250 nm holes (Ted Pella) following theprocess described above.

Phases and Miller indices for the phases in HRTEM image (FIG. 3E) wereassigned based on the two lattice distances d_(hk1) and the anglemeasured from FFT patterns. First, lattice distances d_(hkl) for nickel,nickel (II) oxide, and nickel carbide were calculated based on thelattice parameters obtained from. The measured distances were thencompared to the calculated values and matched within 5% error. The phaseassignment was verified by comparing the angle measured from the FFTpattern with the theoretical value for the obtained orientation, andfurther corroborated using the electron diffraction pattern in FIG. 3D.

Particle size. Particle sizes (see Table 1) were measured from abright-field TEM image using ImageJ (FIG. 7). Confidence interval on themean particle size was calculated assuming normal distribution of theparticle sizes and unknown variance using t-distribution (n=40, α=0.05).Confidence interval on the variance of the particle size was calculatedusing χ² distribution (n=40, α=0.05).

TABLE 1 Particle sizes collected from the bright- field TEM image (seeFIG. 7) Size, N nm 1 37.24 2 19.47 3 33.79 4 25.29 5 30.55 6 17.24 731.06 8 19.04 9 33.05 10 19.86 11 16.73 12 19.59 13 19.03 14 20.41 1522.85 16 26.94 17 17.43 18 18.98 19 23.25 20 22.16 21 15.15 22 19.26 2316.61 24 12.52 25 12.14 26 16.59 27 25.43 28 16.6 29 16.61 30 17.98 3114.29 32 27.28 33 12.82 34 29.34 35 21.67 36 14.88 37 18.95 38 19.95 3921.81 40 30.72

Mechanical characterization. Uniaxial compression experiments wereconducted using in situ nanomechanical instrument, SEMentor (InSEM;Nanomechanics and FEI Quanta 200). Samples were compressed using adiamond flat punch tip with a diameter of 170 μm at a constant strainrate of 10⁻³ s⁻¹. Relative density of each of the structures wascalculated using a CAD model created in Abaqus with average unit cellsizes and beam diameters measured from the SEM images assumingfully-dense beams. Real-time deformation video and the mechanical datawere simultaneously captured during the experiment (not provided).

Specific strength values shown in Table 2 were calculated as the latticestrength divided by the lattice density.

TABLE 2 Specific strength of metal lattices fabricated using metal AMprocesses. Beam Material Lattice Specific Lattice diameter, Strength,Relative density, density, strength, Material Type Process μm MPadensity g/cm³ g/cm³ MPa/(g/cm³) Ti—6Al—4V Cubic Electron 810 23.70 0.0634.43 0.26 84.92 Beam 970 34.70 0.078 0.32 100.42 Melting 1480 89.100.159 0.65 126.50 (EBM) 1780 180.20 0.216 0.88 188.32 Ti—6Al—4VTopology- Selective 406 30.00 n/a 0.50 60.00 optimized Laser Melting(SLM) AlSi10Mg Diamond Direct 405 1.42 0.050 2.67 0.12 10.63 Metal 5024.72 0.075 0.17 23.54 Laser 659 8.54 0.100 0.23 31.98 Sintering 76512.61 0.125 0.29 37.76 (DMLS) 862 17.40 0.150 0.35 43.45 Stainless BCCSelective 162 0.20 0.023 n/a 0.19 1.05 steel 316L Laser 181 0.33 0.0290.23 1.43 Melting 181 0.33 0.029 0.23 1.43 (SLM) 197 0.45 0.034 0.281.61 197 0.45 0.035 0.28 1.61 212 0.58 0.040 0.32 1.81 212 0.60 0.0410.33 1.82 186 0.38 0.031 0.25 1.52 210 0.55 0.039 0.31 1.77 230 0.790.047 0.38 2.08 249 1.00 0.055 0.44 2.27 165 0.32 0.030 0.24 1.33 1660.33 0.032 0.26 1.27 186 0.47 0.036 0.29 1.62 188 0.46 0.034 0.28 1.64222 0.83 0.047 0.38 2.18 211 0.73 0.043 0.34 2.15 Silver OctahedralPointwise 35 0.60 0.065 n/a 0.50 1.20 Spatial 38 1.27 0.270 1.74 0.73Printing NiTi Octahedral Selective 248 21.00 0.252 6.45 1.63 12.92Cellular laser 298 29.00 0.252 1.63 17.84 gyroid melting Sheet (SLM) 21044.00 0.266 1.72 25.65 gyroid Nickel Octet This 0.30 18.17 8.91 2.527.20 work 0.30 17.08 2.55 6.71 0.28 8.91 2.60 3.42 0.27 8.18 2.75 2.98

Pyrolysis was performed in a tube furnace following a two-stepprocedure: (1) at 1000° C. to remove most of the organic content fromthe samples and to consolidate the Ni metal clusters into denserfeatures, which is accompanied by ˜5× linear shrinkage in feature sizeand (2) at 600° C., to reduce the oxygen content in the mostly-Nisamples and to facilitate grain growth. SEM images in FIG. 1I-J show arepresentative 3D Ni architecture and convey that the 10 μm unit cellsand 2 μm-diameter beams in the original polymer-metal structure shrankto ˜2 μm unit cells and ˜300-400 nm diameter beams in the nickelnanolattice. This also implies that 150 nm layer thickness in thepolymer structure corresponds to 30 nm layer thickness in the metalstructure. The zoomed-in image in FIG. 1J shows that the metal beams are˜10%-30% porous caused by pyrolysis.

Chemical composition of the as-fabricated Ni architectures wascharacterized using Energy-Dispersive X-Ray Spectroscopy (EDS), forwhich individual unit cells were fabricated with tetrakaidecahedrongeometries using the same methodology. FIG. 2A shows that thesestructures shrunk from 20 μm-wide unit cells and 2 μm-diameter beams on6 μm pillar supports to 4 μm unit cells and 0.4 μm-diameter beams afterpyrolysis (FIG. 2B). EDS spectrum (FIG. 2D) taken from a beam sectionshown in FIG. 2C reveals the chemical composition to be 91.8 wt % Ni,5.0 wt % 0, and 3.2 wt % C. A Si peak from the substrate is alsopresent. EDS maps in FIG. 2E-H convey a relatively homogeneousdistribution of each element within the printed structure, whichconsists mostly of nickel metal and is not segregated into individualnickel-, carbon-, or oxygen-rich phases.

A few-micron long, 25-100 nm-diameter metal beams that spanned the 1.25μm-wide opening in a silicon nitride membrane were fabricated directlyon the Transmission Electron Microscopy (TEM) grids (FIG. 3A) to analyzethe atomic-level microstructure of pyrolyzed materials. FIG. 3B displaysa bright-field TEM image taken along a portion of that beam that revealsmultiple coalesced grains with mean size of 21.4±2.0 nm.

The electron diffraction pattern (FIG. 3D) taken from the region shownin FIG. 3C conveys a strong Ni signal and a much weaker contributionfrom NiO. A representative high-resolution TEM (HRTEM image (FIG. 3E) ofthe beam edge contains multiple lattice fringes, which allowed thecalculation of interplanar atomic spacings using Fast Fourier transform(FFT). Three distinct spacings were identified: Ni crystals (region 1,spacings of 2.01 Å and 2.04 Å), Ni3C particles (region 2, spacings of1.98 Å and 2.14 Å), and NiO crystals (region 3, spacing of 2.06 Å).Bright-field TEM revealed that Ni crystals occupy >90% of the examinedvolume, NiO<10%, and Ni₃C<1%, consistent with EDS results. TEM analysisfurther revealed the presence of nickel (II) oxide nanoparticles withdiameters of <5 nm at the surface that were likely formed throughsurface oxidation in air after sample preparation. The pyrolysis isequivalent to carbothermal reduction at 1000° C. followed by hydrogenand carbothermal reduction at 600° C., with no oxygen present in theflowing gas.

Literature on this type of thermal treatment reported the composition tobe mainly metallic nickel with a minor amount of nickel carbide and/orcarbon.

Uniaxial compression experiments were performed on four Ni octetnanolattices with relative densities of ˜28-31% and beam sizes of300-400 nm. The experiments were conducted in-situ, in a SEM-basednanomechanical instrument, comprised of a nanoindenter-like module(Nanomechanics, Inc.) inside of SEM chamber (Quanta 200 FEG, FEI), whichenabled observing the deformation while simultaneously collecting loadvs. displacement data. The collected data was converted into engineeringstresses and strains by dividing the load by the sample footprint areaand dividing the displacement by the sample height, respectively. FIG.4A-D shows SEM snapshots obtained during a compression experiment of arepresentative sample together with the stress vs. strain data (FIG.4E). The stress vs. strain data was typical for cellular solidscompressions, with the characteristic elastic loading, plateau, anddensification sections. The arrows on the plot in FIG. 4E are correlatedwith the images in FIG. 4A-D and demarcate specific stages duringcompression: initial contact (region A), elastic deformation (region B),layer-by-layer collapse (region C), and densification (region D). A toeregion in the initial portion of each experiment (not shown) isrepresentative of deformation before establishing full contact betweenthe sample and flat punch indenter tip. The point of full contact wasdetermined using harmonic contact stiffness and SEM video. The slope ofthe elastic loading segment, up to 10-15% strain (region B), was used toestimate structural stiffness of the nanolattices, which ranged from ˜53to 174 MPa. The strength of Ni nanolattices was defined as the maximumstress prior to the first buckling event, marked by open circles in thedata in FIG. 4E, and ranged from 8.2 MPa to 18.2 MPa. The elastic regionwas followed by layer-by-layer layer collapse up to 65% strain (regionC); two of the four samples were unloaded at 30 and 60% strain. The tworemaining samples were compressed to 70-85% strains, reacheddensification (region D) and then unloaded. None of the nanolatticesrecovered after deformation.

FIG. 4F shows the specific strength of Ni nanolattices fabricated inthis work and those of the metallic lattices fabricated using othermetal AM processes as a function of beam diameter on a log-log plot (seeTable 2). Nanocrystalline Ni nanolattices of the disclosure have thespecific strength of 3.0-7.2 MPa/(g/cm³), which is an order of magnitudehigher than that of octahedral silver lattices with ˜40 μm-diameterbeams and ˜3-7× higher than the stainless steel lattices with ˜200μm-diameter beams described in the literature. It appears to be on thesame order as NiTi octahedral lattices with —250 μm-diameter beams andAlSi10Mg diamond lattices with ˜400 μm beams. This suggests that the AMprocess described here is capable of producing architectures withfeature sizes that are an order of magnitude smaller than thosefabricated using existing AM processes while retaining high strength.This is in contrast to all other existing metallic lattices whosestrength rapidly deteriorates with slenderer beams. This trend was usedto extrapolate the specific strength of lattices with beams smaller than40 μm and found that nickel nanolattices are more than four orders ofmagnitude stronger than what is expected for architectures with 0.3 μmfeatures (FIG. 4F). This strength of Ni nanolattices represents a lowerbound because the 10-30% residual porosity lowers the compressivestrength and leads to high sample-to-sample variation.

FIG. 5 shows minimal reported printed feature sizes enabled by thismethod and some other metal AM processes available today. The plottedranges include both layer thickness and minimum lateral feature size.The minimum z-feature is determined by the resolution of a single layerof material. The minimum lateral feature is defined by multiple factors,which include the energy beam spot size and control over the melt pool.The data in FIG. 5 demonstrates that the AM process developed in thiswork is capable of producing features that are an order of magnitudesmaller compared to those produced by other 3D-capable AM processes.Another key aspect of any metal AM process is the throughput. Usinghybrid organic-inorganic photoresist developed in this work allows forwriting speeds of 4-6 mm s⁻¹, which is ˜100 times faster than that forTPL of metal salts. For a typical 300-600nm feature size printed byTPL35, this corresponds to defining 6700 -20000 voxels s⁻¹, a printingspeed that is out of reach for state-of-the-art micro-scale metal AMtechniques, i.e. electrohydrodynamic printing (0.05-300 voxels s⁻¹),local electroplating (0.04-1.0 voxels s⁻¹), focused beam methods(0.01-0.8 voxels s⁻¹), and direct ink writing (0.7-3000 voxels s⁻¹).High scanning speeds and intrinsic advantage of parallelizing lightdelivery using lithographic methods suggest that the presented AMprocess lends itself to efficient scalable manufacturing of metalnano-architectures.

Example 2

Acrylic acid (anhydrous, 99%), titanium(IV) ethoxide (>97%), propyleneglycol monomethyl ether acetate (PGMEA) (>99.5%), and isopropyl alcohol(IPA) (99.7%) were purchased from Sigma Aldrich. Acrylic acid (17.3 g)was slowly added to titanium(IV) ethoxide (13.7 g) in a glovebox (FIG.8A), and the solution was manually agitated. The color of the solutionchanged from yellow to orange, which is indicative of a ligand exchangereaction. This mix was then placed in a vacuum antechamber of theglovebox for 15 min to remove excess ethanol. The resulting solution wastaken out of the glovebox and mixed with 87.7 g of an open-sourceAutodesk PR48 formulation (39.776 wt % Allnex Ebecryl 8210, 39.776 wt %Sartomer SR 494, 0.4 wt % 2,4,6-Trimethylbenzoyl-diphenylphosphineoxide,19.888 wt % Rahn Genomer 1122, 0.160 wt %2,2′-(2,5-thiophenediyl)bis(5-tertbutylbenzoxazole); ColoradoPhotopolymer Solutions) and stirred at room temperature for 1 hr.

A stereolithography-based 3D printer (Autodesk Ember) was used topattern the synthesized titanium-rich photoresist using a layer-by-layerapproach with 25 μm layer thickness (FIG. 8A). Structures with differentgeometries were printed, with the UV exposure of the first layer for14.0 s, four consequent layers for 9.0 s, and all remaining layers for3.5 s. Printed structures were developed in PGMEA for 15 min, followedby IPA wash for 10 min. FIG. 8A shows a representativetitanium-containing polymer scaffold after development.

The final step in this AM process involved placing the printedtitanium-containing polymer structures on a fused quartz boat andpyrolyzed in a tube furnace using 4″ quartz tube under 1 L/min argonflow. The temperature was ramped up to 1000° C. at 2° C./min, kept at1000° C. for 1 hour, and cooled down to room temperature at a naturalrate. FIGS. 8A (bottom) show representative titania structures afterpyrolysis.

Samples were fabricated in two geometries: (1) 10×10×10-unit cell cubiclattices with unit cell dimensions of 1.16±0.10 mm and beam diameters of393±17 μm (FIG. 8A) and (2) 5×5×5-unit cell octet lattices with1.71±0.17 mm unit cell dimensions and 179±5 μm beam diameters. Thesesamples had relative densities that range from 11% to 31%. All sampleswere pyrolyzed in Ar atmosphere at 1000° C., which led to linearshrinkage of 39.0±5.9% and a mass loss of 74.2±2.5%. The final productswere cubic titania lattices with unit cell sizes of 0.66±0.01 mm andbeam diameters of 170±5 μm (FIG. 8A) and octet lattices with unit cellsizes of 1.14±0.01 mm and beam diameters of 115±4 μm (FIG. 8B). These3-dimensional titania architectures appeared white, blue (, black andother colors, which likely stems from (i) a change in the visible lightabsorption of titania as a function of doping with carbon, sulfur andnitrogen, all of which are present in the initial photoresist, and (ii)a contribution to the light absorption by the residual carbon.

FIG. 8C-E show Scanning Electron Microscopy (SEM) (FEI Versa 3DDualBeam) images of the resulting morphology of the pyrolized titaniaoctet lattices at different magnifications. These images revealuniformly sized unit cells and beams with visible layer-to-layertransition patterns, which are inherent for the utilized SL printer(FIG. 8C). The surface of the structure is covered by porousnanocrystalline formations with clearly visible facets and crystalsranging from 20 to 150 nm in size (FIG. 8D-E). SEM Energy-DispersiveX-Ray Spectroscopy (EDS) characterization was conducted with Zeiss1550VP FESEM equipped with Oxford X-Max SDD using a 10 kV electron beam.FIGS. 9A-B and D shows EDS maps of the of the pyrolyzed titanialattices, which convey a uniform distribution of Ti, O and C throughoutthe structure. This EDS spectrum suggests a chemical composition of 46wt % of Ti, 31 wt % of 0, and 23 wt % of C (FIG. 9C). Raman spectroscopy(Renishaw M1000 MicroRaman Spectrometer, 514.5 nm laser) conducted onthe surface of the pyrolyzed samples showed predominantly rutilesignature (FIG. 9F).

FIG. 10 shows the results of microstructural analysis performed on acompressed titania lattice in a Transmission Electron Microscope (FEITecnai F30ST, 300 kV). The sampled titania particles, most likely,belong to the beam surface, since the crystal size considerablydiminishes further away from the surface of the structure, as seen on anSEM image of a beam cross-section (FIG. 10A). TEM images reveal thepresence of TiO₂ crystals (FIG. 10D) with a mean crystal size of59.2±8.0 nm (see FIG. 10B for particle size histogram). Electrondiffraction pattern from a mostly crystalline region of the sample (FIG.10E) corroborates rutile titania as the predominant phase (see FIG.10F). High-resolution TEM image in FIG. 10C demonstrates the presence ofcrystalline and amorphous regions within the sample. FFT analysis of acrystalline region confirms the material to be rutile TiO₂, with 3.20 Ålattice spacing that corresponds to (110) and (110) orientations (FIG.10C, top right). Amorphous regions closer to the beam center correspondto TiO_(1-x)C_(x), with oxygen content varying as a function of depth,as observed on an EDS line spectrum of a beam cross-section.

Uniaxial compression tests on pyrolyzed cubic lattices were performedusing Instron 5569 electromechanical testing machine equipped with anInstron 2525-802 load cell (R.C. 50 kN) at a displacement rate of0.15-0.5 mm/min. The collected load vs. displacement data was convertedinto engineering stresses and strains using the height and the footprintof the structure measured from optical images before compression. FIG.11 shows optical images of the structure during compression (FIG. 11A-D)and representative stress-strain data (FIG. 11E). This data demonstratesthat each compression began with a toe region corresponding to thesample settling into full contact followed by linear elastic regime upto 1-2% strain. Further compression resulted in gradual brittle failureof individual beams and unit cells (see FIG. 11E).

The loading slope was used to calculate the structural elastic modulusto be 0.21-0.37 GPa. The strength was measured as the maximum stressachieved during initial elastic loading and ranged from 2.1 to 4.3 MPa.These strengths and moduli are comparable to strongest reported titaniafoams with 2x higher densities, up to 2.5 MPa at 700 kg/m³, and 2.1 to5.6 times stronger than titania foams with comparable densities (0.8-1.0MPa at 350 kg/m³). The mechanical properties of the architected titanialattices in this work may be further improved by using ahigh-temperature annealing step (1500° C.) that would induce bettersintering of titania particles.

Example 3

Spatial control of catalytic synthesis of carbon nanotubes (CNTs) wasaccomplished using a pattern of nickel NPs. A preparation of anickel-containing resin (see above) was used. Grid patterns were definedwith 5 μm unit cell and 150 nm line thickness on a silicon chip usingtwo-photon lithography. The photoresist pattern was pyrolyzed in argonatmosphere at 900° C., yielding a pattern of 20-150 nm nickelnanoparticles (NiNPs) encapsulated in carbon (FIG. 12A). The NiNPpattern was further process in a forming gas at 900° C. to grow CNTsusing the residual solid carbon source (FIG. 12B).

Other embodiments, combinations and modifications of this invention willoccur readily to those of ordinary skill in the art in view of theseteachings. Therefore, this invention is to be limited only by thefollowing claims, which include all such embodiments and modificationswhen viewed in conjunction with the above specification and accompanyingdrawings.

1. A method for manufacturing a sub-micron architectural material,comprising patterning a hybrid organic-inorganic polymer resincomprising photopolymerizable functional groups and having the generalstructure:M^(n+)(—R′OC—R)_(n) where M is a metal, a metal ion, a metalloid, ametal alloy, a metal oxide, a metal nitride, an inorganic, aninorganic-organic hybrid and/or metal-inorganic composite material,wherein R is a C₂₋₁₀ terminal alkene and R′ is N, O, F, S or Cl andwherein n is 1, 2, 3, 4, 5 or 6, in the presence of a photoinitiatorusing a single or two photon lithography technique to polymerize thepolymer resin and generate the sub-micron architectural material havingdesired characteristic dimension of about 5 nm to 5 micron across. 2.The method of claim 1, wherein the hybrid organic-inorganic polymerresin has the formula R—COR′-M²+-R′OC—R, wherein M is a divalent metalion, alloy, or inorganic material, R is a C₂₋₁₀ terminal alkene and R′is N, O, F, S or Cl.
 3. The method of claim 1, wherein the metal ion isselected from the group consisting of Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺, Be²⁺,Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺, Sc³⁺, Sc²⁺, Sc⁺, Y³⁰, Ti⁴⁺, Ti³⁺, Ti²⁺, Ti²⁺,Zr⁴⁺, Zr³⁺, Zr²⁺, Hf⁴⁺, Hf³⁺, V⁵⁺, V⁴⁺, V³⁺, V²⁺, Nb⁵⁺, Nb⁴⁺, Nb³⁺,Nb²⁺, Ta⁵⁺, Ta⁴⁺, Ta³⁺, Ta²⁺, Cr⁶⁺, Cr⁵⁺, Cr⁴⁺, Cr³⁺, Cr²⁺, Cr⁺, Cr,Mo⁶⁺, Mo⁵⁺, Mo⁴⁺, Mo³⁺, Mo²⁺, Mo⁺, Mo, W⁶⁺, W⁵⁺, W⁴⁺, W³⁺, W²⁺, W⁺, W,Mn⁷⁺, Mn⁶⁺, Mn⁵⁺, Mn⁴⁺, Mn³⁺, Mn²⁺, Mn⁺, Re⁷⁺, Re⁶⁺, Re⁵⁺, Re⁴⁺, Re³⁺,Re²⁺, Re⁺, Re, Fe⁶⁺, Fe⁴⁺, Fe³⁺, Fe²⁺, Fe⁺, Fe, Ru⁸⁺, Ru⁷⁺, Ru⁶⁺, Ru⁴⁺,Ru³⁺, Ru²⁺, Os⁸⁺, Os⁷⁺, Os⁶⁺, Os⁵⁺, Os⁴⁺, Os³⁺, Os²⁺, Os⁺, Os, Co⁵⁺,Co⁴⁺, Co³⁺, Co²⁺, Co⁺, Rh⁶⁺, Rh⁵⁺, Rh⁴⁺, Rh³⁺, Rh²⁺, Rh⁺, Ir⁶⁺, Ir⁵⁺,Ir⁴⁺, Ir³⁺, Ir²⁺, Ir⁺, Ir, Ni³⁺, Ni²⁺, Ni⁺, Ni, Pd⁶⁺, Pd⁴⁺, Pd²⁺, Pd⁺,Pd, Pt⁶⁺, Pt⁵⁺, Pt⁴⁺, Pt³⁺, Pt²⁺, Pt⁺, Cu⁴⁺, Cu³⁺, Cu²⁺, Cu⁺, Ag³⁺,Ag²⁺, Ag⁺, Au⁵⁺, Au⁴⁺, Au³⁺, Au²⁺, Au⁺, Zn²⁺, Zn⁺, Zn, Cd²⁺, Cd⁺, Hg⁴⁺,Hg²⁺, Hg⁺, B³⁺, B²⁺, B⁺, Al³⁺, Al²⁺, Al⁺, Ga³⁺, Ga²⁺, Ga⁺, In³⁺, In²⁺,In¹⁺, Tl³⁺, Tl⁺, Si⁴⁺, Si³⁺, Si²⁺, Sit, Ge⁴⁺, Ge³⁺, Ge²⁺, Ge⁺, Ge, Sn⁴⁺,Sn²⁺, Pb⁴⁺, Pb²⁺, As⁵⁺, As³⁺, As²⁺, As⁺, Sb⁵⁺, Sb³⁺, Bi⁵⁺, Bi³⁺, Te⁶⁺,Te⁵⁺, Te⁴⁺, Te²⁺, La³⁺, La²⁺, Ce⁴⁺, Ce³⁺, Ce²⁺, Pr⁴⁺, Pr³⁺, Pr²⁺, Nd³⁺,Nd²⁺, Sm³⁺, Sm²⁺, Eu³⁺, Eu²⁺, Gd³⁺, Gd²⁺, Gd⁺, Tb⁴⁺, Tb³⁺, Tb²⁺, Tb⁺,Db³⁺, Db²⁺, Ho³⁺, Er³⁺, Tm⁴⁺, Tm³⁺, Tm²⁺, Yb³⁺, Yb²⁺, Lu³⁺ and alloys ofany of the foregoing.
 4. The method of claim 1, wherein the inorganic isa single or mixed oxide, carbide, nitride, silicate, boride of Ti, W,Si, Zr, Al, Y, Cr, Fe, Pb, Co, or a rare earth element.
 5. The method ofclaim 4, wherein the inorganic is selected from the group consisting ofTiO₂, AlO₂, Al₂O₃, ZrO₂, SiC, SiO₂, SiC, CeO₂, and ZnO.
 6. The method ofclaim 1, wherein the metal-inorganic composite comprises Au—Ni—TiO₂,Ni—Co—TiO₂, Ni—Zn—Al₂O₃, or Ni—B—TiO₂.
 7. The method of claim 1, furthercomprising removing non-polymerized resin.
 8. The method of claim 1,further comprising pyrolizing the sub-micron architectural material toremove organic material.
 9. The method of claim 8, wherein thepyrolizing comprises a two-step pyrolysis technique to remove organicmaterial followed by removing oxygen.
 10. The method of claim 8, whereinthe sub-micron architectural material comprises a metal, a metalloidand/or an inorganic structure having a dimension across an axis of ametal, a metalloid and/or a inorganic strut, beam or joint of less than1 micron.
 11. A device comprising the sub-micron architectural materialmade by the method of claim 1, wherein the device comprises a metal, ametalloid, and/or an inorganic scaffold free of organic material havinga strut radial dimension of less than 1 micron.
 12. The device of claim11, wherein the device comprises titania.
 13. The device of claim 11,wherein the device is an electrode, photocell, filter, circuit, waterpurification device or nanocage.